As an on-vehicle wire harness, there is a wire harness that has a nonwoven fabric exterior structure that is formed by heat-molding (hot pressing) a nonwoven fabric in a state covering a wire bundle. As the nonwoven fabric exterior structure, for example, there is a wire protection member disclosed in Patent Literature 1.
FIG. 5 illustrates an explanatory diagram illustrating a conventional wire harness that has a nonwoven fabric exterior structure. As illustrated in FIG. 5, a wire harness 8 has a nonwoven fabric exterior structure 33 that is formed covering a portion of an outer periphery of a wire bundle 12.
FIGS. 6, and 7A, 7B illustrate explanatory diagrams illustrating a manufacturing method of the conventional wire harness 8. In the following, with reference to FIGS. 6 and 7A, 7B, the manufacturing method of the conventional wire harness 8 is described.
As illustrated in FIG. 6, a hot press mold 50 that is used in order to obtain the nonwoven fabric exterior structure 33 has a lower mold 60 and an upper mold 70.
The lower mold 60 is a long member that is formed of a metal and the like having excellent thermal conductivity. A lower mold surface 62 is formed on one main surface (upper surface) of the lower mold 60. Schematically, the lower mold surface 62 is formed in a groove shape that opens upward and on both end sides. The lower mold surface 62 is formed to have a length in a longitudinal direction that is the same as a length of a to-be-protected portion (portion to be covered by the nonwoven fabric exterior structure 33) of the wire bundle 12.
Further, bottoms of two ends of the lower mold surface 62 in the longitudinal direction are formed to have a semi-circular cross section that has an inner diameter corresponding to an external shape of the nonwoven fabric exterior structure 33.
The upper mold 70 is a long member that is formed of a metal and the like having excellent thermal conductivity. On one main surface (lower surface) of the upper mold 70, an upper mold surface 72 is formed in a groove shape having an arc-shaped cross section. The upper mold surface 72 is formed to have a width that allows the upper mold surface 72 to be arranged inside the lower mold surface 62 while allowing the upper opening of the lower mold surface 62 to be filled. A lower surface of the upper mold surface 72 is formed to have a semi-circular cross section that has an inner diameter corresponding to the external shape of the nonwoven fabric exterior structure 33.
By arranging the upper mold surface 72 inside the lower mold surface 62, a space that allows the nonwoven fabric exterior structure 33 to be formed is formed between the upper mold surface 72 and the lower mold surface 62. A heating mechanism (not illustrated in the drawings) such a heater is provided in the lower mold 60 and the upper mold 70.
In the following, a method for manufacturing the nonwoven fabric exterior structure 33 from a nonwoven fabric 3 before molding, using the above-described hot press mold 50, is specifically described.
First, a portion of the wire bundle 12 in a state of being wound with the nonwoven fabric 3 is arranged in the lower mold surface 62 of the lower mold 60.
Specifically, as illustrated in FIG. 7A, the wire bundle 12 oriented along the longitudinal direction in a state where the nonwoven fabric 3 is wound around the wire bundle 12 (configured by a plurality of wires 11) is arranged in the lower mold surface 62. In this case, a winding start edge 3s of the nonwoven fabric 3 is temporarily fixed using a double-sided tape or the like (not illustrated in the drawings) on the wire bundle 12, and a winding end edge 3e of the nonwoven fabric 3 is temporarily fixed via a double-sided tape (not illustrated in the drawings) on an outer peripheral surface of an already-wound portion of the nonwoven fabric 3.
Thereafter, the upper mold surface 72 of the upper mold 70 is inserted into the lower mold surface 62. In this state, the nonwoven fabric 3 is heat-molded (hot-pressed) inside the hot press mold 50. That is, in a state where the nonwoven fabric 3 is pressed between the lower mold surface 62 and the upper mold surface 72, the nonwoven fabric 3 is heated.
Thereafter, when the nonwoven fabric 3 is cooled, a surface of the nonwoven fabric 3 is cured in a shape corresponding to the shapes of the lower mold surface 62 and the upper mold surface 72. Further, overlapping portions of the nonwoven fabric 3 are in a close contact state of being mutually bonded. In this way, the nonwoven fabric exterior structure 33 in a state of covering the wire bundle 12 is formed and the wire harness 8 having the nonwoven fabric exterior structure 33 illustrated in FIG. 5 is completed.